gcc 和 ${CC} 的區別

Question

最近我得到了一塊 NXP imx8 板。 我想測試我的程序。 但它不適用於imx8。

當我使用 aarch64-poky-linux-gcc

$ source /opt/fsl-imx-internal-xwayland/5.15-kirkstone/environment-setup-armv8a-poky-linux
$ aarch64-poky-linux-gcc -o hello hello.c
In file included from hello.c:1:
/opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/x86_64-pokysdk-linux/usr/lib/aarch64-poky-linux/gcc/aarch64-poky-linux/11.2.0/include/stdio.h:27:10: fatal error: bits/libc-header-start.h: No such file or directory
   27 | #include <bits/libc-header-start.h>
      |          ^~~~~~~~~~~~~~~~~~~~~~~~~~
compilation terminated.

當我使用 ${CC}

$ source /opt/fsl-imx-internal-xwayland/5.15-kirkstone/environment-setup-armv8a-poky-linux

${CC} -o hello hello.c # it can work

所以我想知道原因。 我做這件事：

$ echo 'main(){}'|aarch64-poky-linux-gcc -E -v -
Using built-in specs.
COLLECT_GCC=aarch64-poky-linux-gcc
Target: aarch64-poky-linux
Configured with: ../../../../../../work-shared/gcc-11.2.0-r0/gcc-11.2.0/configure --build=x86_64-linux --host=x86_64-pokysdk-linux --target=aarch64-poky-linux --prefix=/usr/local/oe-sdk-hardcoded-buildpath/sysroots/x86_64-pokysdk-linux/usr --exec_prefix=/usr/local/oe-sdk-hardcoded-buildpath/sysroots/x86_64-pokysdk-linux/usr --bindir=/usr/local/oe-sdk-hardcoded-buildpath/sysroots/x86_64-pokysdk-linux/usr/bin/aarch64-poky-linux --sbindir=/usr/local/oe-sdk-hardcoded-buildpath/sysroots/x86_64-pokysdk-linux/usr/bin/aarch64-poky-linux --libexecdir=/usr/local/oe-sdk-hardcoded-buildpath/sysroots/x86_64-pokysdk-linux/usr/libexec/aarch64-poky-linux --datadir=/usr/local/oe-sdk-hardcoded-buildpath/sysroots/x86_64-pokysdk-linux/usr/share --sysconfdir=/usr/local/oe-sdk-hardcoded-buildpath/sysroots/x86_64-pokysdk-linux/etc --sharedstatedir=/usr/local/oe-sdk-hardcoded-buildpath/sysroots/x86_64-pokysdk-linux/com --localstatedir=/usr/local/oe-sdk-hardcoded-buildpath/sysroots/x86_64-pokysdk-linux/var --libdir=/usr/local/oe-sdk-hardcoded-buildpath/sysroots/x86_64-pokysdk-linux/usr/lib/aarch64-poky-linux --includedir=/usr/local/oe-sdk-hardcoded-buildpath/sysroots/x86_64-pokysdk-linux/usr/include --oldincludedir=/usr/local/oe-sdk-hardcoded-buildpath/sysroots/x86_64-pokysdk-linux/usr/include --infodir=/usr/local/oe-sdk-hardcoded-buildpath/sysroots/x86_64-pokysdk-linux/usr/share/info --mandir=/usr/local/oe-sdk-hardcoded-buildpath/sysroots/x86_64-pokysdk-linux/usr/share/man --disable-silent-rules --disable-dependency-tracking --with-libtool-sysroot=/home/bamboo/build/5.15-kirkstone-full/fsl-imx-internal-xwayland/mx8m/yocto/build/tmp/work/x86_64-nativesdk-pokysdk-linux/gcc-cross-canadian-aarch64/11.2.0-r0/recipe-sysroot --with-gnu-ld --enable-shared --enable-languages=c,c++ --enable-threads=posix --enable-multilib --enable-default-pie --enable-c99 --enable-long-long --enable-symvers=gnu --enable-libstdcxx-pch --program-prefix=aarch64-poky-linux- --without-local-prefix --disable-install-libiberty --disable-libssp --enable-libitm --enable-lto --disable-bootstrap --with-system-zlib --with-linker-hash-style=gnu --enable-linker-build-id --with-ppl=no --with-cloog=no --enable-checking=release --enable-cheaders=c_global --without-isl --with-gxx-include-dir=/not/exist/usr/include/c++/11.2.0 --with-build-time-tools=/home/bamboo/build/5.15-kirkstone-full/fsl-imx-internal-xwayland/mx8m/yocto/build/tmp/work/x86_64-nativesdk-pokysdk-linux/gcc-cross-canadian-aarch64/11.2.0-r0/recipe-sysroot-native/usr/aarch64-poky-linux/bin --with-sysroot=/not/exist --with-build-sysroot=/home/bamboo/build/5.15-kirkstone-full/fsl-imx-internal-xwayland/mx8m/yocto/build/tmp/work/x86_64-nativesdk-pokysdk-linux/gcc-cross-canadian-aarch64/11.2.0-r0/recipe-sysroot --enable-standard-branch-protection --enable-poison-system-directories --disable-static --enable-nls --with-glibc-version=2.28 --enable-initfini-array --enable-__cxa_atexit
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 11.2.0 (GCC)
COLLECT_GCC_OPTIONS='-E' '-v' '-mlittle-endian' '-mabi=lp64'
 /opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/x86_64-pokysdk-linux/usr/libexec/aarch64-poky-linux/gcc/aarch64-poky-linux/11.2.0/cc1 -E -quiet -v - -mlittle-endian -mabi=lp64 -dumpbase -
ignoring nonexistent directory "/not/exist/usr/lib/aarch64-poky-linux/11.2.0/include"
ignoring nonexistent directory "/not/exist/usr/local/include"
ignoring nonexistent directory "/opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/x86_64-pokysdk-linux/usr/lib/aarch64-poky-linux/gcc/aarch64-poky-linux/11.2.0/../../../../../aarch64-poky-linux/include"
ignoring nonexistent directory "/not/exist/usr/include/"
#include "..." search starts here:
#include <...> search starts here:
 /opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/x86_64-pokysdk-linux/usr/lib/aarch64-poky-linux/gcc/aarch64-poky-linux/11.2.0/include
 /opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/x86_64-pokysdk-linux/usr/lib/aarch64-poky-linux/gcc/aarch64-poky-linux/11.2.0/include-fixed
End of search list.
# 0 "<stdin>"
# 0 "<built-in>"
# 0 "<command-line>"
# 1 "<stdin>"
main(){}
COMPILER_PATH=/opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/x86_64-pokysdk-linux/usr/libexec/aarch64-poky-linux/gcc/aarch64-poky-linux/11.2.0/:/opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/x86_64-pokysdk-linux/usr/libexec/aarch64-poky-linux/gcc/aarch64-poky-linux/11.2.0/:/opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/x86_64-pokysdk-linux/usr/libexec/aarch64-poky-linux/gcc/aarch64-poky-linux/:/opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/x86_64-pokysdk-linux/usr/lib/aarch64-poky-linux/gcc/aarch64-poky-linux/11.2.0/:/opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/x86_64-pokysdk-linux/usr/lib/aarch64-poky-linux/gcc/aarch64-poky-linux/
LIBRARY_PATH=/opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/x86_64-pokysdk-linux/usr/lib/aarch64-poky-linux/gcc/aarch64-poky-linux/11.2.0/
COLLECT_GCC_OPTIONS='-E' '-v' '-mlittle-endian' '-mabi=lp64'

$ echo 'main(){}'|${CC} -E -v -
Using built-in specs.
COLLECT_GCC=aarch64-poky-linux-gcc
Target: aarch64-poky-linux
Configured with: ../../../../../../work-shared/gcc-11.2.0-r0/gcc-11.2.0/configure --build=x86_64-linux --host=x86_64-pokysdk-linux --target=aarch64-poky-linux --prefix=/usr/local/oe-sdk-hardcoded-buildpath/sysroots/x86_64-pokysdk-linux/usr --exec_prefix=/usr/local/oe-sdk-hardcoded-buildpath/sysroots/x86_64-pokysdk-linux/usr --bindir=/usr/local/oe-sdk-hardcoded-buildpath/sysroots/x86_64-pokysdk-linux/usr/bin/aarch64-poky-linux --sbindir=/usr/local/oe-sdk-hardcoded-buildpath/sysroots/x86_64-pokysdk-linux/usr/bin/aarch64-poky-linux --libexecdir=/usr/local/oe-sdk-hardcoded-buildpath/sysroots/x86_64-pokysdk-linux/usr/libexec/aarch64-poky-linux --datadir=/usr/local/oe-sdk-hardcoded-buildpath/sysroots/x86_64-pokysdk-linux/usr/share --sysconfdir=/usr/local/oe-sdk-hardcoded-buildpath/sysroots/x86_64-pokysdk-linux/etc --sharedstatedir=/usr/local/oe-sdk-hardcoded-buildpath/sysroots/x86_64-pokysdk-linux/com --localstatedir=/usr/local/oe-sdk-hardcoded-buildpath/sysroots/x86_64-pokysdk-linux/var --libdir=/usr/local/oe-sdk-hardcoded-buildpath/sysroots/x86_64-pokysdk-linux/usr/lib/aarch64-poky-linux --includedir=/usr/local/oe-sdk-hardcoded-buildpath/sysroots/x86_64-pokysdk-linux/usr/include --oldincludedir=/usr/local/oe-sdk-hardcoded-buildpath/sysroots/x86_64-pokysdk-linux/usr/include --infodir=/usr/local/oe-sdk-hardcoded-buildpath/sysroots/x86_64-pokysdk-linux/usr/share/info --mandir=/usr/local/oe-sdk-hardcoded-buildpath/sysroots/x86_64-pokysdk-linux/usr/share/man --disable-silent-rules --disable-dependency-tracking --with-libtool-sysroot=/home/bamboo/build/5.15-kirkstone-full/fsl-imx-internal-xwayland/mx8m/yocto/build/tmp/work/x86_64-nativesdk-pokysdk-linux/gcc-cross-canadian-aarch64/11.2.0-r0/recipe-sysroot --with-gnu-ld --enable-shared --enable-languages=c,c++ --enable-threads=posix --enable-multilib --enable-default-pie --enable-c99 --enable-long-long --enable-symvers=gnu --enable-libstdcxx-pch --program-prefix=aarch64-poky-linux- --without-local-prefix --disable-install-libiberty --disable-libssp --enable-libitm --enable-lto --disable-bootstrap --with-system-zlib --with-linker-hash-style=gnu --enable-linker-build-id --with-ppl=no --with-cloog=no --enable-checking=release --enable-cheaders=c_global --without-isl --with-gxx-include-dir=/not/exist/usr/include/c++/11.2.0 --with-build-time-tools=/home/bamboo/build/5.15-kirkstone-full/fsl-imx-internal-xwayland/mx8m/yocto/build/tmp/work/x86_64-nativesdk-pokysdk-linux/gcc-cross-canadian-aarch64/11.2.0-r0/recipe-sysroot-native/usr/aarch64-poky-linux/bin --with-sysroot=/not/exist --with-build-sysroot=/home/bamboo/build/5.15-kirkstone-full/fsl-imx-internal-xwayland/mx8m/yocto/build/tmp/work/x86_64-nativesdk-pokysdk-linux/gcc-cross-canadian-aarch64/11.2.0-r0/recipe-sysroot --enable-standard-branch-protection --enable-poison-system-directories --disable-static --enable-nls --with-glibc-version=2.28 --enable-initfini-array --enable-__cxa_atexit
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 11.2.0 (GCC)
COLLECT_GCC_OPTIONS='-march=armv8-a+crc+crypto' '-fstack-protector-strong' '-O2' '-D' '_FORTIFY_SOURCE=2' '-Wformat=1' '-Wformat-security' '-Werror=format-security' '-E' '-v' '-mlittle-endian' '-mabi=lp64'
 /opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/x86_64-pokysdk-linux/usr/libexec/aarch64-poky-linux/gcc/aarch64-poky-linux/11.2.0/cc1 -E -quiet -v -isysroot /opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/armv8a-poky-linux -D _FORTIFY_SOURCE=2 - -march=armv8-a+crc+crypto -mlittle-endian -mabi=lp64 -Wformat=1 -Wformat-security -Werror=format-security -fstack-protector-strong -O2 -dumpbase -
ignoring nonexistent directory "/opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/armv8a-poky-linux/usr/local/include"
ignoring nonexistent directory "/opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/x86_64-pokysdk-linux/usr/lib/aarch64-poky-linux/gcc/aarch64-poky-linux/11.2.0/../../../../../aarch64-poky-linux/include"
#include "..." search starts here:
#include <...> search starts here:
 /opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/x86_64-pokysdk-linux/usr/lib/aarch64-poky-linux/gcc/aarch64-poky-linux/11.2.0/include
 /opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/armv8a-poky-linux/usr/lib/aarch64-poky-linux/11.2.0/include
 /opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/x86_64-pokysdk-linux/usr/lib/aarch64-poky-linux/gcc/aarch64-poky-linux/11.2.0/include-fixed
 /opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/armv8a-poky-linux/usr/include/
End of search list.
# 0 "<stdin>"
# 0 "<built-in>"
# 0 "<command-line>"
# 1 "/opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/armv8a-poky-linux/usr/include/stdc-predef.h" 1 3 4
# 0 "<command-line>" 2
# 1 "<stdin>"
main(){}
COMPILER_PATH=/opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/x86_64-pokysdk-linux/usr/libexec/aarch64-poky-linux/gcc/aarch64-poky-linux/11.2.0/:/opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/x86_64-pokysdk-linux/usr/libexec/aarch64-poky-linux/gcc/aarch64-poky-linux/11.2.0/:/opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/x86_64-pokysdk-linux/usr/libexec/aarch64-poky-linux/gcc/aarch64-poky-linux/:/opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/x86_64-pokysdk-linux/usr/lib/aarch64-poky-linux/gcc/aarch64-poky-linux/11.2.0/:/opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/x86_64-pokysdk-linux/usr/lib/aarch64-poky-linux/gcc/aarch64-poky-linux/
LIBRARY_PATH=/opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/x86_64-pokysdk-linux/usr/lib/aarch64-poky-linux/gcc/aarch64-poky-linux/11.2.0/:/opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/armv8a-poky-linux/lib/:/opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/armv8a-poky-linux/usr/lib/aarch64-poky-linux/11.2.0/:/opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/armv8a-poky-linux/usr/lib/
COLLECT_GCC_OPTIONS='-march=armv8-a+crc+crypto' '-fstack-protector-strong' '-O2' '-D' '_FORTIFY_SOURCE=2' '-Wformat=1' '-Wformat-security' '-Werror=format-security' '-E' '-v' '-mlittle-endian' '-mabi=lp64'

我發現他們都使用 aarch64-poky-linux-gcc。 但我仍然不知道它們之間的區別。

Answer 1

gcc是命令的名稱。 您的 shell 將在path中查找它。

${CC}是一個變量替換。 你的 shell 會在 shell 進程的環境中尋找它。

Answer 2

gcc是您機器的編譯器。 您可以像這樣找到哪個和位置：

• readlink -f $(which gcc) ：這將顯示您使用的程序的路徑
• gcc --version ：將顯示您的 gcc 編譯器的版本

如果您在 PC 中構建，那么gcc將為 x86 架構構建程序。 在您的情況下，您需要一個編譯器來為 arm64 架構生成程序（開源是aarch64-linux-gnu-gcc ，但提供者通常會為您提供一個修改后的工具鏈，其中包含編譯器和所有必要的庫/頭文件。

當你交叉編譯時，你必須“ source ”一個環境文件，這將修改終端中的環境變量如果你源環境文件這將創建環境變量CC ，這將包含編譯器的路徑以及編譯器的一些參數.

如果您運行echo ${CC}您將看到工具鏈和參數。

這個想法始終是擁有一個不依賴於操作系統的隔離環境，主機 PC 的 gcc 版本，這就是為什么為您提供編譯器並且您必須使用${CC}交叉編譯到架構臂，這是imx SOC的基礎